Headphones are a pair of small loudspeakers designed to be held close to the user's ears. Different types of headphones have different sound reproduction characteristics.
Headphones may be used both with fixed equipment such as CD or DVD players, home theater, personal computers and with portable devices (e.g. digital audio/player/mp3 player, mobile phone, etc.).
Headphones are available with low or high impedance (typically measured at 1 kHz). Low-impedance headphones are in the range 16 to 32 ohms whereas high-impedance headphones are about 100-600 ohms. As the impedance of a pair of headphones increases, more voltage (at a given current) is required to drive it, and the loudness of the headphones for a given voltage decreases. The impedance of headphones is of concern because of the output limitations of amplifiers. A modern pair of headphones is driven by an amplifier, with lower impedance headphones presenting a larger load. Amplifiers are not ideal; they also have some output impedance that limits the amount of power they can provide. If the amplifier's output impedance is large compared to the impedance of the headphones, a significantly higher distortion will occur. Therefore, lower impedance headphones will tend to be louder and more efficient, but will also demand a more capable amplifier. Higher impedance headphones will be more tolerant of amplifier limitations, but will produce less volume for a given output level.
Sensitivity is a measure of how effectively an earpiece converts an incoming electrical signal into an audible sound. It thus indicates how loud the headphones will be for a given electrical drive level. It can be measured in decibels of sound pressure level per milliwatt, or dB SPL/mW, which may be abbreviated to dB/mW. The sensitivity of a given pair of headphones is fixed and usually varies between about 80 and 125 dB/mW.
Everyone uses headphones the same way as the others, but since hearing capabilities change from one person to the other, the audio signals to which the users of the headphones are able to listen, change from one person to the other, depending primarily on one's hearing capabilities. The term “hearing range” usually relates to the range of frequencies that can be heard by humans, though it can also refer to the range of levels. The human range is commonly taken as 20 to 20,000 Hz, though there is considerable variations between different individuals, especially at high frequencies, and a gradual decline with age is considered to be normal. Individual hearing range varies according to the general condition of the human's ears. The range shrinks during life, usually beginning at around age of eight with the upper frequency limit being reduced. Women typically experience a lesser degree of hearing loss than men, with a later onset. Men have approximately 5 to 10 dB greater loss in the upper frequencies by the age of 40. On top of that, there may also be substantial differences between one's hearing capabilities in one ear compared to the other.
In view of the above, it is clear that the listening experience of each individual could be enhanced if the audio output to which he/she is listening, is adapted to fit that individual. Unfortunately, there are no adequate solutions to this problem yet, so that the options available for the users who wish to enhance their listening experience by having earphones that meet their needs, are for example the following:
Retrieving information form professional audio review websites that offer insight and commentary;
Retrieving information from bulletin boards and other public forums that provide comments from actual customers of the products;
Looking up for retailers who carry the items the individual is interested in, and finding out if it is possible to try them out; and
Testing models owned by friends or colleagues.
Although these solutions may help an individual in assessing possible earphones that would better suit his/her needs, still they cannot be considered as solutions to the problem of tailoring the earphones to each specific individual based on his/her own hearing capabilities. No suitable solution has yet been provided to this problem, and the present invention seeks to provide such a solution.
Few solutions for personalized headphones are known in the art, among which are for example the following ones:
US 20140016795 discloses a personalized headphone comprising a first speaker and a second speaker; a cord, having a removable connector plug at a distal end adapted to maintain audio communication with the first speaker and/or the second speaker, wherein the cord comprises an audio device connector plug adapted to maintain electrical communication with a digital playback device, wherein the audio output of the speakers has a built-in preconfigured equalizer personalized to a user's age, audio file format, audio file data encoding rate and music genre.
US 20060050908 describes a system and method that determines parameters for rendering headphone audio information, based on a user's preferred acoustic rendering in a non-headphone environment. A user configures a loudspeaker-based system for a preferred ambiance. Microphones on a head-mounted device then detect the audio signals received by the user in this environment. These detected signals are compared to the audio information that is being provided by the user's audio system and the differences are used to characterize the user's particular environment. Based on this characterization, when the user uses a headphone device to listen to the audio information, a headphone driver modifies the audio information to produce audio signals at the speakers in the user's headphone to effectively reproduce the audio signals that would have been produced at the user's ears by the loudspeakers in the user's particular environment.